Update changelog: add bash 5.3+ fix, link all issues/PRs

Add #572/#571 entry, add "already fixed" section for #630/#529/#539,
and convert all issue/PR references to markdown links.

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

CHANGELOG.md

@@ -4,9 +4,15 @@
 
 ### Fixed
 
-- **Brainstorm server on Windows**: Auto-detect Windows/Git Bash (`OSTYPE=msys*`, `MSYSTEM`) and switch to foreground mode, fixing silent server failure caused by `nohup`/`disown` process reaping. Applies to all Windows shells (CMD, PowerShell, Git Bash) since they all route through Git Bash. (fixes #737, based on #740)
-- **Portable shebangs**: Replace `#!/bin/bash` with `#!/usr/bin/env bash` in all 13 shell scripts. Fixes execution on NixOS, FreeBSD, and macOS with Homebrew bash where `/bin/bash` is outdated or missing. (closes #700)
-- **POSIX-safe hook script**: Replace `${BASH_SOURCE[0]:-$0}` with `$0` in `hooks/session-start` and polyglot-hooks docs. Fixes 'Bad substitution' error on Ubuntu/Debian where `/bin/sh` is dash. (closes #553)
+- **Brainstorm server on Windows**: Auto-detect Windows/Git Bash (`OSTYPE=msys*`, `MSYSTEM`) and switch to foreground mode, fixing silent server failure caused by `nohup`/`disown` process reaping. Applies to all Windows shells (CMD, PowerShell, Git Bash) since they all route through Git Bash. ([#737](https://github.com/obra/superpowers/issues/737), based on [#740](https://github.com/obra/superpowers/pull/740))
+- **Portable shebangs**: Replace `#!/bin/bash` with `#!/usr/bin/env bash` in all 13 shell scripts. Fixes execution on NixOS, FreeBSD, and macOS with Homebrew bash where `/bin/bash` is outdated or missing. ([#700](https://github.com/obra/superpowers/pull/700), dupes: [#747](https://github.com/obra/superpowers/pull/747))
+- **POSIX-safe hook script**: Replace `${BASH_SOURCE[0]:-$0}` with `$0` in `hooks/session-start` and polyglot-hooks docs. Fixes 'Bad substitution' error on Ubuntu/Debian where `/bin/sh` is dash. ([#553](https://github.com/obra/superpowers/pull/553))
+- **Bash 5.3+ hook hang**: Replace heredoc (`cat <<EOF`) with `printf` in `hooks/session-start`. Fixes indefinite hang on macOS with Homebrew bash 5.3+ caused by a bash regression with large variable expansion in heredocs. ([#572](https://github.com/obra/superpowers/pull/572), [#571](https://github.com/obra/superpowers/issues/571))
+
+### Already fixed on dev (closed PRs)
+
+- **Windows hook quoting** ([#630](https://github.com/obra/superpowers/pull/630), [#529](https://github.com/obra/superpowers/issues/529)): `hooks.json` already uses escaped double quotes on dev.
+- **Windows symlink path** ([#539](https://github.com/obra/superpowers/pull/539)): Closed — the PR introduced a bug (literal `~` in path alongside `$env:USERPROFILE`). Current docs are correct.
 
 ### Known Issues