fix(files): keep attachment markdown refs from resolving into the workspace, and render files without chat line breaks (#503 review)

- A markdown preview opened by attachment id under a bare file name
  (attachment cards, history drawer) no longer resolves relative refs
  against the workspace root: filePreviewText carries attachmentId, and
  the rebase pass turns those images into their alt text and unwraps
  those links. Absolute-path and workspace previews are unchanged.
- _renderMarkdown(text, { breaks = true } = {}): the File Viewer passes
  breaks: false, so a hard-wrapped paragraph renders as one paragraph;
  the Response Viewer keeps a <br> per newline.
- Absolute paths linkified inside a rendered document now carry the
  preview's data-session-id.
- CLAUDE.md, architecture-invariants and the Working-With-Files wiki page
  now say that only an in-workspace path clicked in the terminal keeps
  the tail viewer.
- Tests in test/file-preview-markdown.test.ts for all three fixes,
  including an end-to-end run of the shipping app.js + marked + DOMPurify.

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

CLAUDE.md

@@ -295,7 +295,7 @@ Codeman is a Claude Code session manager with web interface and autonomous Ralph
 
 **File Viewer edit mode** (issue #212): the file-preview overlay edits workspace text files in place — `GET .../file-content?edit=1` + `PUT /api/sessions/:id/file-content`, policy in `src/config/file-editing.ts`. This is a **third file surface and the only one that WRITES**: read-path confinement (realpath + workspace + ownership) plus sensitive/blocked/`.git` denies and an extension **allowlist**; writes are `wx`-temp + rename (no `O_CREAT` anywhere = edit-in-place is structural); optimistic concurrency via sha256 `baseHash` → 409. ⚠️ `edit=1` never truncates and the client must never save a plain-preview buffer (the 500-line truncation would silently delete the rest). ⚠️ CRLF/UTF-8 guards: EOL re-applied server-side, non-UTF-8 refused via round-trip compare. → [architecture-invariants#file-viewer-edit-mode](docs/architecture-invariants.md#file-viewer-edit-mode), `docs/file-viewer-edit-plan.md`
 
-**File Viewer text view: rendered markdown + Lines/Wrap toggles** (`_renderFilePreviewText()` in panels-ui.js): a `.md`/`.markdown` opens RENDERED by default with an `MD` pill back to source; the plain-text view has `Lines` (CSS-counter gutter) and `Wrap` toggles. ⚠️ ONE markdown pipeline: the viewer calls `_renderMarkdown()` (marked + the DOMPurify allowlist, the Response Viewer's) and binds the Response Viewer's click delegate (`_bindResponseViewerInteractions`) on the preview body for code-copy buttons and path links; never a second parser or handler. ⚠️ The document is built inside a `<template>` (a detached div with `innerHTML` set starts fetching every `<img src>` before the rewrite), then `_rebaseFilePreviewMarkdownRefs()` points relative images at the workspace-confined `file-raw` under the document's directory and root-relative ones under the workspace root (never a widened route; a failed load degrades to alt text), after `decodeURIComponent`ing the ref and dropping `?query`/`#fragment` (marked percent-encodes destinations, and the route encodes again), and turns workspace links into `a.rv-path` carrying `data-session-id` for the delegate, stripping the `target` marked gave them. ⚠️ The container carries `data-i18n-skip` or the translator rewrites the document's prose. ⚠️ Toggles are per-device localStorage keys (`codeman:filePreview*`), never `SettingsUpdateSchema`; Lines/Wrap are class flips on the ONE `<pre>`, with rules scoped `.file-preview-body > pre.file-preview-text` so they never leak into the document's code blocks. Markdown fetches `lines=10000` (the route ceiling), other text keeps 500. ⚠️ `md` stays OUT of `FILE_PREVIEW_EXTENSIONS`: a printed `.md` path keeps the tail viewer (live follow); the rendered view is the Files panel's. Tests: `test/file-preview-markdown.test.ts`. → [architecture-invariants#file-viewer-text-view-rendered-markdown-and-text-toggles](docs/architecture-invariants.md#file-viewer-text-view-rendered-markdown-and-text-toggles)
+**File Viewer text view: rendered markdown + Lines/Wrap toggles** (`_renderFilePreviewText()` in panels-ui.js): a `.md`/`.markdown` opens RENDERED by default with an `MD` pill back to source; the plain-text view has `Lines` (CSS-counter gutter) and `Wrap` toggles. ⚠️ ONE markdown pipeline: the viewer calls `_renderMarkdown(text, { breaks: false })` (marked + the DOMPurify allowlist, the Response Viewer's; chat keeps the default `breaks: true`, a file must not turn every hard wrap into a `<br>`) and binds the Response Viewer's click delegate (`_bindResponseViewerInteractions`) on the preview body for code-copy buttons and path links; never a second parser or handler. ⚠️ The document is built inside a `<template>` (a detached div with `innerHTML` set starts fetching every `<img src>` before the rewrite), then `_rebaseFilePreviewMarkdownRefs()` points relative images at the workspace-confined `file-raw` under the document's directory and root-relative ones under the workspace root (never a widened route; a failed load degrades to alt text), after `decodeURIComponent`ing the ref and dropping `?query`/`#fragment` (marked percent-encodes destinations, and the route encodes again), and turns workspace links into `a.rv-path` carrying `data-session-id` for the delegate (the linkifier's absolute paths get it too), stripping the `target` marked gave them. ⚠️ A preview opened by attachment id under a bare file name (attachment cards, history drawer: the registry keeps no relative path) has no directory, so its workspace refs degrade (images to alt text, links to their text), never resolve against the workspace root. ⚠️ The container carries `data-i18n-skip` or the translator rewrites the document's prose. ⚠️ Toggles are per-device localStorage keys (`codeman:filePreview*`), never `SettingsUpdateSchema`; Lines/Wrap are class flips on the ONE `<pre>`, with rules scoped `.file-preview-body > pre.file-preview-text` so they never leak into the document's code blocks. Markdown fetches `lines=10000` (the route ceiling), other text keeps 500. ⚠️ `md` stays OUT of `FILE_PREVIEW_EXTENSIONS`: only an IN-WORKSPACE `.md` path clicked in the TERMINAL keeps the tail viewer (live follow); the Files panel, chat paths, out-of-workspace terminal paths and attachment cards all reach `openFilePreview()` and render it. Tests: `test/file-preview-markdown.test.ts`. → [architecture-invariants#file-viewer-text-view-rendered-markdown-and-text-toggles](docs/architecture-invariants.md#file-viewer-text-view-rendered-markdown-and-text-toggles)
 
 **Files panel search** (COD-236, the `q` param on `GET /api/sessions/:id/files`): `compileFileQuery()` (`utils/file-query.ts`, pure) compiles the query into a predicate the server-side walk prunes with; a query returns a FLAT match list and the walk recurses past non-matching directories. An empty, whitespace-only or overlong (`MAX_QUERY_LENGTH`, 256) query compiles to `null`, keeping the default tree response byte-identical. ⚠️ **Never compile a glob into a RegExp** (`*a*a*a…` backtracks and freezes the event loop for the whole server): `globMatch()` is a two-pointer wildcard walk. → [architecture-invariants#files-panel-search](docs/architecture-invariants.md#files-panel-search)