feat(vault): vault config + vault purge (PRD §7.1)

Add a persistent typed config file and the two remaining settings /
maintenance verbs, then wire the config into the CLI's agent auto-spawn
so a saved interval actually takes effect. CLI-only: no protocol, agent,
or TUI changes — the agent still receives knobs as the launch flags it
already accepted.

Config: $XDG_CONFIG_HOME/vault/config.toml, modeled as a known-key
registry. `vault config set <key> <value>` validates the key and parses
the value to its type (typos and non-numeric values are rejected, not
silently kept); `unset` clears; `get` with no key lists every known key
with its effective value (--json on all three). Atomic writes (tempfile
+ rename, mirroring vault-store::write_atomic). Recognised keys this
release: clipboard.clear_secs and agent.idle_lock_secs (both u64, 0
disables); the registry is shaped to grow into the rest of §7.1.

Auto-spawn: spawn_and_connect sources those two knobs from config and
appends them as agent launch flags, so config wins over the agent's
env/default on this path; a manually launched agent is unaffected. A
malformed config is reported and skipped rather than blocking the spawn
(verified live).

Purge: vault purge drops a running agent's in-memory keys (best-effort
Lock via a direct, hint-free connect; never auto-spawns) and removes the
on-disk item cache (vault_store::default_data_dir()). Confirmation-gated
like remove (--force to skip; required when stdin isn't a TTY); an absent
cache is success.

New toml dependency (MIT/Apache, within deny.toml's allow-list);
vault-cli gains dirs/serde/tempfile/vault-store as normal deps.

Tests: config registry units (round-trips, unknown-key + bad-value
rejection, 0 accepted, KNOWN_KEYS reachable by all three ops, TOML serde
round-trip) and a pure agent_args test for the config→launch-flags
mapping. Verified live: get/set/unset, JSON output, rejection paths,
auto-spawn flag pass-through, malformed-config degradation, and purge
(lock + cache removal + no-TTY refusal).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: UnbreakableMJ

CHANGELOG.md

@@ -10,6 +10,35 @@ range may break in any release.
 
 ### Added
 
+- **`vault config` + `vault purge` (PRD §7.1).** A persistent, typed config
+  file and the two remaining settings/maintenance verbs.
+  - **Config file** at `$XDG_CONFIG_HOME/vault/config.toml`, modeled as a
+    *known-key registry*: `vault config set <key> <value>` validates the key
+    and parses the value to its type (a typo or non-numeric value is rejected,
+    not silently kept), `vault config unset <key>` clears it, and
+    `vault config get` with no key lists every known key with its effective
+    value (`--json` on all three). Writes are atomic (tempfile + rename).
+    Recognised keys this release: `clipboard.clear_secs` and
+    `agent.idle_lock_secs` (both `u64`, `0` disables).
+  - **Wired into auto-spawn.** When the CLI starts the agent, it sources those
+    two knobs from the config and passes them as launch flags — so a saved
+    `clipboard.clear_secs` finally has a persistent home instead of being
+    flag/env-only. On the auto-spawn path the config value populates the agent
+    flag (winning over `$VAULT_CLIPBOARD_CLEAR_SECS`); a manually launched
+    agent is unaffected, and a malformed config is reported and skipped rather
+    than blocking the spawn.
+  - **`vault purge`** drops a running agent's in-memory keys (best-effort
+    `Lock`, never auto-spawning) and removes the on-disk item cache
+    (`$XDG_DATA_HOME/vault`). Confirmation-gated like `remove` (`--force` to
+    skip; required when stdin isn't a TTY); an absent cache is success.
+  - CLI-only slice — no protocol, agent, or TUI changes; the agent still
+    receives knobs as the launch flags it already accepted. New `toml`
+    dependency (MIT/Apache, within the `deny.toml` allow-list).
+  - Tests: config registry units (set/get/unset round-trips, unknown-key and
+    bad-value rejection, `0` accepted, `KNOWN_KEYS` reachable by all three
+    ops, TOML serde round-trip) and a pure `agent_args` test for the
+    config→launch-flags mapping (both set / one set / none).
+
 - **Clipboard hardening — clear-on-lock sweep, backend trait, OSC52 fallback,
   configurable interval.** Closes the secret-can-outlive-the-agent limitation
   tracked since the M5 copy slice, and delivers PRD §7.5 in its

Cargo.lock

@@ -47,6 +47,7 @@ thiserror = "2"
 clap = { version = "4", features = ["derive", "wrap_help"] }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
+toml = "0.8"
 tokio = { version = "1", features = ["rt-multi-thread", "macros", "net", "io-util", "signal", "sync", "time", "fs"] }
 tokio-test = "0.4"
 zeroize = { version = "1", features = ["zeroize_derive"] }

Cargo.toml

@@ -44,6 +44,23 @@ sibling of the `vault` binary, then `$PATH` (override with
 `$VAULT_AGENT_BIN`; opt out per-call with `--no-auto-spawn`). A spawned
 agent logs to `agent.log` beside the socket.
 
+## Configuration
+
+Persistent settings live at `$XDG_CONFIG_HOME/vault/config.toml`, managed with
+`vault config`:
+
+```sh
+vault config get                          # list every known key + value
+vault config set clipboard.clear_secs 45  # validated; writes config.toml
+vault config set agent.idle_lock_secs 600
+vault config unset clipboard.clear_secs
+```
+
+Recognised keys: `clipboard.clear_secs` (auto-clear window, `0` disables) and
+`agent.idle_lock_secs` (idle-lock timeout, `0` disables). When the CLI
+auto-starts the agent, these populate its launch flags. Wipe the on-disk item
+cache (and drop a running agent's keys) with `vault purge`.
+
 ## Repository layout
 
 ```

README.md

@@ -28,14 +28,16 @@ workspace = true
 default = ["cli"]
 cli = []
 
-[dev-dependencies]
-tempfile = { workspace = true }
-
 [dependencies]
 anyhow = { workspace = true }
 clap = { workspace = true }
+dirs = { workspace = true }
+serde = { workspace = true }
 serde_json = { workspace = true }
+tempfile = { workspace = true }
 tokio = { workspace = true }
+toml = { workspace = true }
 zeroize = { workspace = true }
 vault-core = { path = "../vault-core" }
 vault-ipc = { path = "../vault-ipc" }
+vault-store = { path = "../vault-store" }