dashboard: distinguish missing-dir vs missing-git in approval_diff

CLAUDE.md

@@ -156,7 +156,18 @@ in.
     listing containers (deep-linked to their per-container UI) + pending
     approvals. Same aesthetic.
   - Firewall opens 7000, 8000, 8100–8999 when the module is enabled.
-- 🔜 Phase 7 — dashboard approval-actions + live message-flow + xterm.js terminal
+- ✅ Phase 7 — polish:
+  - 7a — dashboard `POST /approve/<id>` / `/deny/<id>` buttons + unified
+    diff (via `similar`) of applied vs proposed `agent.nix`.
+  - 7b — broker broadcast channel + `/messages/stream` SSE + live message-flow
+    panel (cyan `→` sent / green `✓` delivered, 200 row cap).
+  - 7c — `ApprovalResolved` helper events into the manager's inbox
+    (`SYSTEM_SENDER` + `HelperEvent` JSON). Manager harness recognises and
+    logs them distinctly.
+  - 7d — default `MemoryMax=2G` + `CPUQuota=50%` applied to every managed
+    container via `/run/systemd/system/container@<NAME>.service.d/hyperhive-limits.conf`
+    drop-in (regenerated on every spawn / rebuild).
+  - 7e — damocles migration plan (`docs/damocles-migration.md`).
 
 ## Approval flow (Phase 5)
 

docs/damocles-migration.md

@@ -0,0 +1,73 @@
+# Migrating damocles onto hyperhive
+
+The plan calls out damocles → hyperhive as a future migration. This doc lays
+out the options + recommended path. Not yet executed.
+
+## Current state (separate from hyperhive)
+
+`damocles` is a declarative nixos-container on `muede-lpt2`:
+
+- Declared in `nixosConfigurations/muede-lpt2/containers.nix`
+- Built from `nixosConfigurations/damocles/` (claude-container.nix + extras)
+- Bind-mounts (RO unless noted):
+  - `/etc/nix/distributed-build-key`
+  - `/persist/damocles-ssh`
+  - `/persist/damocles-lab` (RW — persistent work dir)
+- `privateNetwork = false`
+- Has its own systemd-services override (`TimeoutStopSec = 60s`, `RestartSec = 5s`)
+- Hosts the user's primary day-job Claude Code session, not part of the swarm
+
+## Options
+
+### A. Sub-agent under hive-c0re
+Make damocles a `hive-agent-damocles` (or whatever short name fits the 9-char cap).
+hive-c0re owns its lifecycle; its config flake is the manager-editable
+`/var/lib/hyperhive/agents/damocles/config/`.
+
+Pros: uniform — message broker, dashboard, approval flow apply to damocles too.
+Cons: a lot of damocles-specific state (bind-mounts, ssh keys, build keys) has to
+be modeled as per-agent config. Today's `agent.nix` schema doesn't support
+declaring bind-mounts; would need to extend. And the user's day-job session
+becoming subject to hive-c0re lifecycle (restarts on rebuild) is invasive.
+
+### B. Peer container (broker-integrated, lifecycle-independent)
+Keep damocles declarative; have its harness install `hive-ag3nt` and connect to
+the broker via a bind-mounted socket. damocles can send/recv messages with
+other sub-agents but is not managed by hive-c0re.
+
+Pros: low blast radius. damocles keeps its bind-mounts + its own restart policy.
+Manager can route messages to it (it's just another inbox key on the broker).
+Cons: two lifecycle mechanisms coexist forever; "damocles" doesn't appear in the
+dashboard's container list (it filters `hive-` and `hm1nd`).
+
+### C. Don't migrate
+damocles stays out of hyperhive. The two systems coexist; the user's day-job
+Claude and the swarm are deliberately separate.
+
+Pros: zero work; aligns with the actual usage pattern (day-job vs. experiment).
+Cons: no message routing between damocles and the swarm.
+
+## Recommended
+
+**C for now, B once cross-pollination is wanted.** Hyperhive's invariants
+(11-char container names, manager-driven lifecycle, sealed `applied/` config)
+fit poorly with damocles's role as the user's working Claude. Wait until there's
+a concrete reason to wire them together (e.g. "I want to ask hm1nd from inside
+damocles") and then do B — extend the broker socket bind into damocles and
+install `hive-ag3nt` there. No need to subsume damocles under hive-c0re.
+
+If/when option B is taken:
+
+1. Add `${hyperhive.packages.${system}.default}/bin/hive-ag3nt` (or just
+   `pkgs.hyperhive`) to `nixosConfigurations/damocles/claude-container.nix`.
+2. Bind-mount `/run/hyperhive/agents/damocles/` into damocles at `/run/hive/`.
+   On the host, this is just another dir hive-c0re needs to know about —
+   maybe expose a "peer agents" registration mechanism in the broker.
+3. Run `hive-ag3nt serve` as a systemd unit inside damocles (separate from
+   the user's interactive claude session — broker peer, not turn-loop).
+4. Optionally: add a `hive-c0re register-peer damocles` admin verb so the
+   container appears in `list()` and the dashboard. (Or just hard-list it.)
+
+A is on the table only if the user's workflow shifts toward "the swarm IS the
+day-job environment" — at which point damocles dissolves into a `hive-agent-*`
+naturally.

hive-c0re/src/dashboard.rs

@@ -157,14 +157,22 @@ async fn render_approvals(approvals: &[Approval]) -> String {
 }
 
 async fn approval_diff(agent: &str, commit_ref: &str) -> String {
-    let applied = Coordinator::agent_applied_dir(agent).join("agent.nix");
     let proposed = Coordinator::agent_proposed_dir(agent);
+    if !proposed.exists() {
+        return format!(
+            "(proposed dir {} does not exist — agent destroyed?)",
+            proposed.display()
+        );
+    }
+    if !proposed.join(".git").exists() {
+        return format!("(no git repo at {})", proposed.display());
+    }
+    let applied = Coordinator::agent_applied_dir(agent).join("agent.nix");
     let applied_text = std::fs::read_to_string(&applied).unwrap_or_default();
-    let proposed_text = match git_show(&proposed, commit_ref).await {
-        Ok(s) => s,
-        Err(e) => return format!("(error reading proposed agent.nix: {e:#})"),
-    };
-    unified_diff(&applied_text, &proposed_text)
+    match git_show(&proposed, commit_ref).await {
+        Ok(s) => unified_diff(&applied_text, &s),
+        Err(e) => format!("(error: {e:#})"),
+    }
 }
 
 async fn git_show(proposed_dir: &Path, commit_ref: &str) -> Result<String> {
@@ -173,7 +181,13 @@ async fn git_show(proposed_dir: &Path, commit_ref: &str) -> Result<String> {
         .args(["show", &format!("{commit_ref}:agent.nix")])
         .output()
         .await
-        .context("git show")?;
+        .with_context(|| {
+            format!(
+                "spawn `git show` in {} (HYPERHIVE_GIT={})",
+                proposed_dir.display(),
+                std::env::var("HYPERHIVE_GIT").unwrap_or_else(|_| "<unset>".into()),
+            )
+        })?;
     if !out.status.success() {
         anyhow::bail!(
             "git show {commit_ref}:agent.nix failed: {}",