fix(fs): persist read window offset in the read card meta

An empty read window (byte cap below the first selected line: `lines: []`
with `totalLines > 0`) dropped `offset` from the persisted presentation
meta, so a replayed read card could not report where the window starts or
where a continuation resumes. Carry `offset` on `FsReadMeta`,
`ReadResultView`, and the `presentationMeta` projection, and validate it in
`readMetaFromMeta` (1-based integer; the first line number may not fall
below it). Re-record the ACP fixtures and the cordis api catalog.

Also correct the Note's `parallel-file-reads` golden path
(examples/tui-agent -> apps/cli) and record the pre-card replay-degradation
tradeoff in the Decision section.

packages/fs/tool-fs/src/read.ts

@@ -125,6 +125,7 @@ export function applyReadTool(ctx: Context, caps: ReadToolCaps): void {
         const lang = langFromPath(value.path)
         return {
           path: value.path,
+          offset: value.offset,
           lines: value.lines.map(({ number, text }) => ({ number, text })),
           totalLines: value.totalLines,
           ...lang === undefined ? {} : { lang },
@@ -186,6 +187,7 @@ export function applyReadTool(ctx: Context, caps: ReadToolCaps): void {
       return {
         card: 'read',
         path: meta.path,
+        offset: meta.offset,
         lines: meta.lines,
         totalLines: meta.totalLines,
         ...meta.lang === undefined ? {} : { lang: meta.lang },