feat(uploads): prompt uploads take documents

The Attach button, the Compose and paste-dialog pickers, terminal drop and the
clipboard now take documents beside images and videos: the office formats
pdf/docx/pptx/xlsx/zip and the text family txt/md/csv/tsv/json/log/yaml/yml/xml.

A document is admitted by its name's extension (the MIME a phone attaches to a
.md is anyone's guess), buffered under the same 50MB image cap, and judged on
its bytes by the same fail-closed sniffer: a magic-number signature for the
binary formats, UTF-8 with no NUL byte for text. It is saved under a sanitized
stem of its name, so Q3 report.pdf is findable as paste-<ts>-<hex>-Q3-report.pdf.

sh/py/js/html are refused by name with a clear 400. That is a scope choice, not
a security property: file-raw already serves non-media text inert, so this keeps
the server from storing what it would serve or an agent could run, and html and
svg are the ones deliberately kept out. One client classifier (_promptAttachKind)
now returns image, video or document, and the server's dispatch mirrors it: an
image MIME wins whatever the name says, a document extension takes the document
branch, and a foreign extension with no image MIME is refused only after the
image sniff fails, so nothing the image path accepted by its bytes is lost.

docs/wiki/Mobile-Guide.md

@@ -66,7 +66,8 @@ autocorrect: Enter adds a new line, and only Send delivers the text, as one past
 by Enter, so your line breaks reach the agent intact. Anything already typed on the terminal
 prompt moves into the editor when it opens. Drafts are kept per session and in memory only,
 so switching tabs keeps them and a page reload forgets them; a dot on the key shows a draft
-is parked. The editor's Image button attaches photos or videos and puts their paths into the draft.
+is parked. The editor's Attach button attaches photos, videos or documents and puts their paths
+into the draft.
 Destructive commands need a double press, so you cannot fire `/clear` with a stray thumb. On
 Codex sessions the bar also shows `⇧←` and `⇧→`, the Shift-modified arrows Codex binds to
 editing the last queued message and walking the prompt stack.
@@ -103,12 +104,16 @@ into the Run dropdown.
 ## The Attach button
 
 The toolbar's **Attach** button (the picture icon beside the mic) is the keyboard-down way to
-hand the agent a photo or a video. One tap opens the camera and photo library sheet, nothing
-else: no editor, no keyboard. The chosen files upload and their paths land on the prompt, so
-you then tap the terminal, write the rest of your message and press Enter. Videos (mp4, webm,
-mov, m4v, ogv) upload as recorded, up to 1 GB each by default
-(`CODEMAN_MAX_PASTE_VIDEO_BYTES` on the server changes it), so a long 4K clip takes a moment
-on the way up.
+hand the agent a photo, a video or a document. One tap opens the system's sheet (camera,
+photo library, or a file from Files or a cloud drive), nothing else: no editor, no keyboard.
+The chosen files upload and their paths land on the prompt, so you then tap the terminal,
+write the rest of your message and press Enter. Videos (mp4, webm, mov, m4v, ogv)
+upload as recorded, up to 1 GB each by default (`CODEMAN_MAX_PASTE_VIDEO_BYTES` on the
+server changes it), so a long 4K clip takes a moment on the way up. Documents are PDFs,
+Office files (docx, pptx, xlsx), zips and plain-text formats such as txt, md, csv and json;
+a document keeps the plain-letters part of its name in the saved file, so the agent and you
+can tell the uploads apart. See [Working With Files](Working-With-Files) for where they land and how long they
+stay.
 
 If the keyboard was up when you tapped Attach, iOS closes it to show the photo sheet and does
 not bring it back, so the tap on the terminal is how you get it again. That is the system's
@@ -120,7 +125,7 @@ anything you had already typed, so you can write in front of a path, fix a word,
 **Use terminal keyboard** hands a single-line message back the other way, onto the prompt,
 so neither surface holds a half of your message. A multi-line message cannot make that trip
 (the prompt is a single line), so it stays parked as a draft and the dot on the Compose key
-shows it is waiting. The Compose editor's own Image button remains for the times you are
+shows it is waiting. The Compose editor's own Attach button remains for the times you are
 already writing in the editor.
 
 ## Tapping, links and copying

docs/wiki/Settings-Reference.md

@@ -217,7 +217,7 @@ Some things are configured before the server starts, not in the UI:
 | `CODEMAN_ALLOW_UNAUTHENTICATED_NETWORK` | Acknowledges exposing the server with no password.                  |
 | `CODEMAN_BASE_URL`                  | Mounts Codeman under a sub-path behind a reverse proxy that forwards the prefix unchanged. See [Remote Access](Remote-Access). |
 | `CODEMAN_MAX_DOWNLOAD_BYTES`        | Cap on raw file bodies and downloads. 2 GB by default, `0` for none.    |
-| `CODEMAN_MAX_PASTE_IMAGE_BYTES`     | Cap on one pasted, dropped or attached image. 50 MB by default.         |
+| `CODEMAN_MAX_PASTE_IMAGE_BYTES`     | Cap on one pasted, dropped or attached image or document. 50 MB by default. |
 | `CODEMAN_MAX_PASTE_VIDEO_BYTES`     | Cap on one attached video (phone Attach, drop). 1 GB by default; videos stream to disk, so this bounds disk use, not memory. |
 | `CODEMAN_MAX_REMOTE_FILE_SSH`       | Concurrent ssh reads for files in remote cases. 4 by default.           |
 | `CODEMAN_PATH_PROBE_TIMEOUT_MS`     | How long a linked case's folder may take to answer before it is shown as unreachable. 1500 ms by default; raise it for a slow but healthy mount. |

docs/wiki/Working-With-Files.md

@@ -168,17 +168,39 @@ blocks sensitive trees. In multi-user mode a non-admin gets only their own user
 root, because per-user spaces live inside the home directory and a home-directory root would
 expose everyone.
 
-## Images into a session
+## Files into a session
 
-Paste from the clipboard or drag and drop straight onto the terminal. The image is written
+Paste from the clipboard or drag and drop straight onto the terminal. The file is written
 where the agent can read it and the reference is inserted into your prompt. On a phone, the
-toolbar's Attach button opens the camera or photo library, videos included, and puts the path
-on your prompt, where it behaves like text you typed; the Image button inside the Compose
-editor does the same into the editor. Dropping a video onto the terminal works the same way.
+toolbar's Attach button opens the camera, photo library or files, and puts the path on your
+prompt, where it behaves like text you typed; the Attach button inside the Compose editor
+does the same into the editor. Dropping a video or a document onto the terminal works the
+same way.
 
-HEIC images from an iPhone are converted to JPEG on the way in.
-Videos (mp4, webm, mov, m4v, ogv) are stored as recorded, up to 1 GB each by default
-(`CODEMAN_MAX_PASTE_VIDEO_BYTES`); they stream to disk rather than through server memory.
+Images (png, jpg, gif, webp, bmp, heic) go in after a re-encode on the device, and HEIC from
+an iPhone is converted to JPEG. Videos (mp4, webm, mov, m4v, ogv) are stored as recorded,
+up to 1 GB each by default (`CODEMAN_MAX_PASTE_VIDEO_BYTES`); they stream to disk rather than
+through server memory. Documents are the office formats (pdf, docx, pptx, xlsx, zip) and the
+text family (txt, md, csv, tsv, json, log, yaml, yml, xml). Each is checked on the way in,
+against its file signature for the binary formats and against its encoding for text (UTF-8,
+no NUL bytes), so a script renamed to `.pdf` is refused while a `.txt` can hold any text at
+all. Files with script or page extensions (sh, py, js, html) are not accepted, since a prompt
+upload is something for the agent to read, not something for Codeman to store and serve. A
+document keeps a trimmed copy of its original name, letters, digits, dot, dash and underscore
+with anything else turned into a dash, so `Q3 report.pdf` is findable as
+`paste-<time>-<id>-Q3-report.pdf`; a name made entirely of other characters saves without
+one. Uploads are refused for remote (SSH) sessions, whose working directory is on the other
+host.
+
+Uploads land in `.codeman-uploads/` inside the case, next to the code the agent is working
+on, because that is the one path a local agent, a container and a remote host all see the
+same way. The first upload writes a `.gitignore` of `*` into `.codeman-uploads/`, so the
+directory ignores itself and your repository never picks the files up, while your own ignore file is
+left alone; a `.gitignore` you already had there is never overwritten. Files older than seven
+days are swept hourly, and the directory goes when the last session of the case is closed (a
+session that is only detached keeps it). Earlier releases wrote to `.claude-images/`; that
+directory is still swept and cleaned up the same way for one release so a case in use before
+the move is not left with stray files.
 
 ## Generated artifacts