tcl: Phase 5d/5e/5f — file ops, clock locale+scan, socket -async

Phase 5d (file metadata + ops):
- 11 SX primitives: file-size/mtime/stat/isfile?/isdir?/readable?/writable?/
  delete/mkdir/copy/rename — wrap Unix.stat/access/unlink/mkdir/rename
- Tcl `file` subcommands real (were stubs): isfile, isdir, readable,
  writable, size, mtime, atime, type, mkdir, copy, rename, delete
- file delete/copy/rename strip leading-`-` flags
- +10 idiom tests

Phase 5e (clock options + scan):
- clock-format extended to (t fmt tz), tz ∈ utc|local
- Added specifiers: %y, %I, %p, %w, %%
- New clock-scan SX primitive — format-driven parser + manual timegm
- Tcl clock format/scan accept -format, -timezone, -gmt 0|1
- +5 idiom tests

Phase 5f (socket -async):
- socket-connect-async SX primitive: Unix.set_nonblock + connect, catches
  EINPROGRESS; returns channel immediately
- channel-async-error: Unix.getsockopt_error
- Tcl `socket -async host port`; `fconfigure $sock -error`
- Connection completes on writable; canonical fileevent pattern works
- +3 idiom tests

Bug fix: tcl-call-proc was discarding :fileevents/:timers/:procs updates
made inside Tcl procs (only :commands forwarded). Now forwards full
result-interp as base, restoring caller's frame/stack/result/output/code.
This was masked until socket-async made fileevent-from-inside-proc the
natural pattern.

test.sh inner timeout bumped 1200s→2400s (post-merge JIT remains slow).

376/376 green.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/tcl/test.sh

@@ -57,7 +57,7 @@ cat > "$TMPFILE" << EPOCHS
 (eval "tcl-test-summary")
 EPOCHS
 
-OUTPUT=$(timeout 1200 "$SX_SERVER" < "$TMPFILE" 2>&1)
+OUTPUT=$(timeout 2400 "$SX_SERVER" < "$TMPFILE" 2>&1)
 [ "$VERBOSE" = "-v" ] && echo "$OUTPUT"
 
 # Extract summary line from epoch 11 output