Persist bash history and bake shell quality-of-life defaults

Two changes that address a longstanding frustration: bash history is
lost on every container recreate, and the container's ~/.bashrc and
~/.inputrc are stock Debian (no history tuning, no prefix search on
arrow keys, no integrations).

Added a named volume 'devbox-shell-history' mounted at ~/.cache/bash
with HISTFILE pointing there; history now survives 'docker compose up
--force-recreate'. The volume is added to both docker-compose.yml and
docker-compose.shared.yml, and ~/.cache/bash is registered in the
entrypoint ownership-fix loop per the AGENTS.md convention.

Baked rootfs/home/developer/.bash_aliases (sourced automatically by
Debian's default ~/.bashrc) and rootfs/home/developer/.inputrc into
the image. They give new containers: 100k-entry timestamped dedup
history with per-prompt flush, Up/Down arrow prefix history search,
case-insensitive coloured completion, aliases that prefer eza and
bat when present, git shortcuts, interactive rm/mv/cp, zoxide and
fzf (via 'fzf --bash') integration, and a [devbox] prompt marker.
The fzf integration uses 'fzf --bash' because we install fzf from
GitHub releases, not apt — the apt-path key-bindings aren't present.

Users who prefer their host's own shell config can uncomment two
commented bind-mount lines in docker-compose.yml to shadow the
baked defaults.

DOCKER_HUB.md

@@ -227,6 +227,7 @@ Understanding what survives container restarts and what doesn't:
 | `/home/developer/.aws` | Host bind mount | ✅ Yes — lives on host | AWS credentials/SSO cache |
 | `/home/developer/.local/share/opencode` | Named volume (if configured) | ✅ Yes — Docker volume | Session history, memory, auth tokens |
 | `/home/developer/.local/state/opencode` | Named volume (if configured) | ✅ Yes — Docker volume | TUI settings (theme, toggles) |
+| `/home/developer/.cache/bash` | Named volume `devbox-shell-history` | ✅ Yes — Docker volume | Bash history (`$HISTFILE`) — survives container recreate |
 | `/home/developer/.local/share/uv` | Named volume (if configured) | ✅ Yes — Docker volume | Python installs, uv tool installs |
 | `/home/developer/.rustup` | Named volume (if configured) | ✅ Yes — Docker volume | Rust toolchains |
 | `/home/developer/.cargo` | Named volume (if configured) | ✅ Yes — Docker volume | Cargo binaries, registry cache |
@@ -239,6 +240,7 @@ Understanding what survives container restarts and what doesn't:
 - **opencode config** is auto-generated from `OPENCODE_PROVIDER` env var on each start if no existing config is found. To persist config changes, mount the config directory from the host (see Custom opencode Config below).
 - **opencode data** (session history, memory) is lost on container recreation unless you add a named volume.
 - **TUI settings** (theme, toggles) are lost on container recreation unless you add the `devbox-state` named volume.
+- **Bash history** persists via the `devbox-shell-history` volume mounted at `~/.cache/bash`. `HISTFILE` is pre-configured; no setup required.
 - **Python installs** via `uv python install` are lost on container recreation unless you add the `devbox-uv` named volume.
 - **Rust toolchains** via `rustup-init` are lost on container recreation unless you add the `devbox-rustup` and `devbox-cargo` named volumes.
 - **AWS SSO tokens** persist across restarts when `~/.aws` is mounted (recommended for Bedrock users).
@@ -463,6 +465,19 @@ docker compose run --rm devbox        # direct to opencode
 docker compose run --rm devbox bash   # interactive shell
 ```
 
+## Shell defaults
+
+The image ships baked shell defaults in `~/.bash_aliases` and `~/.inputrc`:
+
+- **Prefix history search** on Up/Down arrows (type `git `, press Up, walk back through prior `git ...` commands only). Ctrl-Up / Ctrl-Down still step through full history.
+- **Persistent history** via `$HISTFILE=~/.cache/bash/history`, backed by the `devbox-shell-history` named volume. Survives container recreate. 100 000 entries, time-stamped, dedup.
+- **Case-insensitive tab completion** and coloured completion lists.
+- **Aliases** — `ls`/`ll`/`la` → `eza`, `cat` → `bat`, `gs`/`gd`/`gl` for git, interactive `rm`/`mv`/`cp`.
+- **Integrations** — `zoxide` (`z <fragment>`), `fzf` key bindings (`Ctrl-R`, `Ctrl-T`).
+- **`[devbox]` prompt prefix** so you always know you're in the container.
+
+To override with your host's own `~/.bash_aliases` / `~/.inputrc`, uncomment the matching bind-mount lines in `docker-compose.yml`.
+
 ## What's Included
 
 ### Base image (`latest`)