fix(ui-conversation): decorate pasted file paths as whole tokens

Closed @"…" paths and unquoted @ tokens with a separator or extension now decorate in full, matching the spans the sent message renders as references.

packages/client/ui-conversation/src/client/input/decorations.ts

@@ -2,7 +2,7 @@
  * Plain-text reference scan (the plain-text-reference decision;
  * see .agents/notes/archived/architecture/2026-07-25-web-input-machine-and-slash-pipeline.md):
  * a `/name` or `@name` token whose name is on the trigger's lexicon, and
- * syntax-recognizable `@dir/` folder tokens. Pure derivation — the editor's
+ * syntax-recognizable `@path` file and folder tokens. Pure derivation — the editor's
  * text-ref entity transform consumes these ranges; editing the text out of
  * match shape simply drops the range next scan.
  */
@@ -10,9 +10,9 @@
 /**
  * One plain-text reference range (the plain-text-reference decision;
  * see .agents/notes/archived/architecture/2026-07-25-web-input-machine-and-slash-pipeline.md):
- * a `/name` or `@name` token
- * whose name is on the trigger's lexicon. Pure derivation — editing the text
- * out of match shape simply drops the range next scan.
+ * a `/name` or `@name` token whose name is on the trigger's lexicon, or an
+ * `@path` file or folder token. Pure derivation — editing the text out of
+ * match shape simply drops the range next scan.
  */
 export interface TextRefRange {
   readonly start: number
@@ -23,30 +23,40 @@ export interface TextRefRange {
 /** Token matcher: a trigger char at line start or after whitespace, then a word-ish name (never crosses \n). */
 const TEXT_REF_RE = /(^|\s)([/@])([\w-]+)/g
 /** One `@` path token: a quoted path through its closing quote or line end, or an unquoted run. */
-const PATH_TOKEN_RE = /(^|\s)(@(?:"[^"\n]*"?|[^\s"]+))/g
+const PATH_TOKEN_RE = /(^|\s)(@(?:"[^"\n]*"?|[^\s"]\S*))/g
 /**
- * What may follow an unquoted or open-quoted folder token's slash: trailing
- * punctuation, then whitespace or the draft end. The class matches the
- * punctuation that `folderReferenceRule` in ui-reference strips from a sent token.
+ * Punctuation that ends prose rather than a path: the characters the
+ * sent-message file and folder rules in ui-reference strip from the end of an
+ * unquoted token.
  */
-const FOLDER_END_RE = /[.,;:!?，。；：！？]*(?:\s|$)/y
+const TRAILING_PUNCTUATION = new Set('.,;:!?，。；：！？')
+/** An unquoted token names a path only with a separator or an extension; a bare `@name` stays plain until a lexicon claims it. */
+const PATH_LIKE_RE = /^@.*[/\\.]/u
 
 /**
- * End of the whole `@dir/` folder token at `start`, so `@src/a.ts` and
- * `@"a/b c.md"` never match their directory prefix. A closed quote ends the
- * token when it directly follows the slash; an unquoted or open-quoted token
- * (a drill in progress) ends at its last slash.
+ * End of the whole `@path` file or folder token at `start`, so a path is never
+ * cut at its directory prefix. A closed quote ends at its quote and an
+ * unquoted token with a separator or extension drops trailing punctuation,
+ * the spans the sent-message rules render. An open quote (a folder drill in
+ * progress) ends at its last slash when only trailing punctuation and
+ * whitespace or the draft end follow it.
  * @param draft - draft text.
  * @param start - offset of the token's `@`.
  * @param token - the path token at `start`.
- * @returns the folder token's end offset, or undefined for a non-folder token.
+ * @returns the token's end offset, or undefined when it names no path.
  */
-function folderEnd(draft: string, start: number, token: string): number | undefined {
-  if (token.startsWith('@"') && token.endsWith('/"')) return start + token.length
+function pathEnd(draft: string, start: number, token: string): number | undefined {
+  if (!token.startsWith('@"')) {
+    let length = token.length
+    while (TRAILING_PUNCTUATION.has(token.charAt(length - 1))) length -= 1
+    return PATH_LIKE_RE.test(token.slice(0, length)) ? start + length : undefined
+  }
+  if (token.length > 3 && token.endsWith('"')) return start + token.length
   const slash = token.lastIndexOf('/')
-  if (slash < 0 || token.endsWith('"')) return undefined
-  FOLDER_END_RE.lastIndex = start + slash + 1
-  return FOLDER_END_RE.test(draft) ? start + slash + 1 : undefined
+  if (slash < 0) return undefined
+  let next = start + slash + 1
+  while (TRAILING_PUNCTUATION.has(draft.charAt(next))) next += 1
+  return next === draft.length || /\s/u.test(draft.charAt(next)) ? start + slash + 1 : undefined
 }
 /**
  * What may follow a `/name` token: whitespace or the draft end, the boundary
@@ -85,7 +95,7 @@ export function scanTextRefs(
   let path: RegExpExecArray | null
   while ((path = PATH_TOKEN_RE.exec(draft)) !== null) {
     const start = path.index + (path[1]?.length ?? 0)
-    const end = folderEnd(draft, start, path[2] ?? '')
+    const end = pathEnd(draft, start, path[2] ?? '')
     if (end !== undefined && !out.some(range => range.start < end && range.end > start)) {
       out.push({ start, end, trigger: '@' })
     }

packages/client/ui-conversation/tests/draft-document.client.spec.ts

@@ -812,10 +812,14 @@ describe('plain-text reference catalogs', () => {
     ])
   })
 
-  it('matches whole folder tokens, never the directory prefix of a pasted file path', () => {
-    expect(scanTextRefs('@src/deep/file.txt @"/a/nv/SM100 ISA.html" 看 @"a/ b.md" @src/.env @src/de', new Map())).toEqual([])
-    const text = '@"dir a/" @src/deep/。 @dir/ 请看 @"src/"，然后 @"open dir/ x'
-    expect(scanTextRefs(text, new Map()).map(range => text.slice(range.start, range.end)))
+  it('matches whole file and folder path tokens, never a directory prefix', () => {
+    const slices = (text: string) => scanTextRefs(text, new Map()).map(range => text.slice(range.start, range.end))
+    expect(slices('@src/deep/file.txt， @"/a/nv/SM100 ISA.html" 看 @"a/ b.md"。 @src/.env @C:\\src\\a.ts @src/de'))
+      .toEqual(['@src/deep/file.txt', '@"/a/nv/SM100 ISA.html"', '@"a/ b.md"', '@src/.env', '@C:\\src\\a.ts', '@src/de'])
+    expect(slices('@"dir a/" @src/deep/。 @dir/ 请看 @"src/"，然后 @"open dir/ x'))
       .toEqual(['@"dir a/"', '@src/deep/', '@dir/', '@"src/"', '@"open dir/'])
+    expect(slices('@person @"" @"a/b')).toEqual([])
+    expect(slices('@"open @')).toEqual([])
+    expect(slices('drill @"open dir/。')).toEqual(['@"open dir/'])
   })
 })

packages/client/ui-conversation/tests/input-bar.client.spec.tsx

@@ -1875,13 +1875,13 @@ describe('decorations', () => {
     expect(shell.snapshot.draft).toBe('see @src/components/')
   })
 
-  it('a pasted file path stays plain: only a whole folder token decorates', async () => {
+  it('a pasted path decorates as one whole file or folder token', async () => {
     const { view, shell, textarea } = bench()
     const marks = () => [...view.container.querySelectorAll('[data-composer-text-ref]')].map(el => el.textContent)
     const text = 'read @"/a/nv/SM100 ISA.html" and @src/deep/file.txt then @src/deep/ first'
     fireEvent.paste(textarea, { clipboardData: { items: [], getData: () => text } })
     await vi.waitFor(() => { expect(shell.snapshot.draft).toBe(text) })
-    expect(marks()).toEqual(['@src/deep/'])
+    expect(marks()).toEqual(['@"/a/nv/SM100 ISA.html"', '@src/deep/file.txt', '@src/deep/'])
   })
 
   it('a plain-text reference keeps its DOM node while typing ahead of it (bug #2793 regression)', () => {