fix: pos media sync finds nothing when the source dir is a symlink

GNU find (default -P) does not descend a command-line symlink to a
directory, so `find $HOME/Music ...` returned zero files and the tool
reported '0 added, 0 updated, 0 unchanged' without creating the target.
Switch to `find -H` (follows only command-line symlinks; inner-symlink
semantics unchanged).

AGENT_TODO.md

@@ -42,6 +42,7 @@ summary (newest last).
 
 ## Done
 
+- **2026-08-15** — Fix `pos media sync` reporting success with 0 files when the source is a symlink: it enumerated with plain `find "$SRC"`, and GNU find (default `-P`) does not descend a command-line symlink to a directory — `~/Music -> /mnt/hdd/…/music` therefore yielded zero matches, the loop never ran, and the tool printed `0 added, 0 updated, 0 unchanged` without creating the target dir (live-box report). Switched to `find -H "$SRC"` (follows only command-line symlinks; inner-symlink semantics unchanged). howto/media.md sync section notes symlinked sources are followed. Caught live, not by the 46-case stub suite (which used a real temp dir source — lesson: add a symlink-root fixture). Verified: `printf 'y\n' | bash bin/pos-media-sync --mp3 --dry-run` now lists all 31 mp3s as "would copy"; `make gen && make check` green.
 - **2026-08-14** — `pos system backup` — smart USB detection: lsblk TRAN (lsusb/by-id cross-check), mount offer for plugged-in-but-unmounted sticks, sha256-verified copy (stub-suite 54/54).
 - **2026-08-05** — `pos communication telegram` — `--parse-mode` (plain/markdown/html).
 - **2026-08-05** — doc/code sync gate — `make gen` + `make check` + pre-commit hook.

DOC/howto/media.md

@@ -112,6 +112,10 @@ a no-op. Preview before copying with `--dry-run`:
 pos media sync --mp4 --dry-run   # shows "would copy" list + counts, copies nothing
 ```
 
+The source folder may be a symlink to a library elsewhere
+(`~/Music -> /mnt/data/music`) — it is followed, the artist/album tree is
+mirrored under the symlink's target.
+
 | Flag | Meaning |
 |------|---------|
 | `--mp3` | Sync only `*.mp3` (neither flag = both) |

bin/pos-media-sync

@@ -128,7 +128,7 @@ while IFS= read -r f; do
     else
         unchanged=$((unchanged + 1))
     fi
-done < <(find "$SRC" "${find_expr[@]}" | sort)
+done < <(find -H "$SRC" "${find_expr[@]}" | sort)
 
 if [ "$DRY_RUN" -eq 1 ]; then
     echo "DRY RUN — nothing copied. Would sync: ${added} new, ${updated} updated, ${unchanged} unchanged → $dest_root"