feat(story-mode): draw a Claude session's turns as comic pages, live

Story Mode is an opt-in header button (showStoryButton, per device, default
off, kept off phones) that opens the active Claude Code session as comic pages:
one page per prompt, panels for reading code, planning, helpers, edits, tests
(POW/KRAK), questions and saving, each with a plain story caption and a
Director's cut caption naming the tools. Files open in the existing file
preview, the code page opens the exact diff, a test board opens the output,
and a running turn redraws as Claude works.

Server: GET /api/sessions/:id/story (experimental) reads a bounded tail of the
session's own transcript. A pure core (src/story-mode.ts) reduces lines,
joins tool calls with their results, splits turns at prompts and
turn_duration, and groups events into at most 12 panels; Bash calls are
sorted by what the command does. The reader (src/story-reader.ts) caches
reduced entries and reads only appended bytes while the file grows.

Frontend: story-mode.js (canvas frame engine, live refresh from transcript and
hook SSE events plus a poll while a turn runs, details drawer, the wire) and
story-mode.css, with two self-hosted OFL comic fonts.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

.changeset/story-mode.md

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+---
+'aicodeman': minor
+---
+
+Story Mode draws what Claude Code does as a comic. Turn on **Story Mode** in App Settings → Header buttons (per device, off by default) and its button opens the active Claude session as comic pages: one page per prompt, with panels for reading code, planning, calling in helpers, editing, running tests (POW! or KRAK!), asking you and saving, each with a plain caption anyone can follow. The **Director's cut** switch names every tool call instead and lists all of them beside the page. Everything is clickable: a file opens in the file viewer, the code page shows the exact diff of Claude's edits, a test board shows the output with clickable `file:line` links, and a helper shows what it was asked and what it answered. A turn that is still running redraws as Claude works, new panels inking in where blue-pencil roughs stood. The data comes from `GET /api/sessions/:id/story`, an experimental read-only endpoint.