Windows bootstrap fix + TMPDIR portability + README prereqs

[evikzub]

Summary

Three small fixes surfaced while installing the plugin on Windows (Git Bash / MSYS2). Each commit is independent — feel free to cherry-pick.

• fix(hooks) — the SessionStart and PostToolUse hook commands in hooks/hooks.json redirect stderr to .remember/logs/hook-errors.log via 2>>. Bash opens the redirect target before running the script, so on the first invocation in a fresh project (when the .remember/logs/ directory does not yet exist) the redirect fails and the hook script never runs — even though the script itself contains mkdir -p .remember/logs near the top. Classic chicken-and-egg. Prefix both commands with mkdir -p ... && so the redirect target is guaranteed to exist.

• fix(user-prompt-hook) — user-prompt-hook.sh reads /tmp/claude-ctx-pct. Works on macOS/Linux, but on Windows Git Bash the /tmp mapping may differ from what other processes that write the file expect. Honor \$TMPDIR with a /tmp fallback. No behavior change on default macOS/Linux.

• docs(readme) — the Requirements section listed Python / bash / Claude CLI but not jq (which log.sh and session-start-hook.sh rely on). Add jq + coreutils, and a short Windows subsection documenting the supported POSIX environments (Git Bash/MSYS2, WSL) and the need to install jq / python3 alongside Git for Windows.

Reproduction

On a fresh project (Windows or Unix):

1. Install the plugin.
2. Start a new Claude Code session.
3. Hook logs a "No such file or directory" warning on .remember/logs/hook-errors.log. Subsequent invocations succeed (the hook script's own mkdir -p eventually runs once something else creates the directory), but the first session's SessionStart memory injection is lost.

Test plan

• Applied the same two code changes locally at ~/.claude/plugins/cache/claude-plugins-official/remember/0.5.0/ on Windows 11 with Git Bash + MSYS2 + jq + Python 3.11. Warning disappears on new-project startup; memory pipeline runs normally.
• scripts/run-tests.sh — not run (Windows MSYS2 test env not set up by this contributor). Upstream test run would be appreciated.

Not changed

• nohup usage in session-start-hook.sh / post-tool-hook.sh — on Windows MSYS2 this doesn't truly detach, but fixing it properly likely requires a platform-specific backgrounding strategy. Out of scope for this PR.

[fdaviddpt]

Closing — the three fixes in this PR have been addressed in #33:

1. hooks.json mkdir → fix: centralize .remember/ bootstrap + portability fixes (Windows, macOS, Haiku) #33 commit 1 (bootstrap-dirs.sh — more architectural fix)
2. TMPDIR portability → fix: centralize .remember/ bootstrap + portability fixes (Windows, macOS, Haiku) #33 commit 2 (centralized SYS_TMPDIR, cherry-picked your approach)
3. README Windows prereqs → fix: centralize .remember/ bootstrap + portability fixes (Windows, macOS, Haiku) #33 commit 3 (cherry-picked your documentation)

Thank you @evikzub for the excellent Windows work! You were the first to surface the TMPDIR issue and document the Windows prerequisites clearly. Your contributions are credited in the commit messages. We also approved your PR #29 (Python detection + slug fix) separately — that one stands on its own and is ready to merge. Looking forward to more contributions!