config PRs: remove the hive's config-PR webhook, poll and core merge

An operator's merge on the forge deploys a config PR through
swarm-controller's DeployRequest{rev}. The hive-side path that queued a
MergeConfigPr approval and merged the PR as `core` goes:

- the `/webhook/config-pr` receiver, its HMAC secret, the WebhookRegister
  boot node and the org-hook registration; the hive vhost's `/webhook/`
  location
- the 5-minute config-PR poll
- ApprovalKind::MergeConfigPr, its dashboard card, and the deploy DAG it
  drove (DeployWindow, MergeVerify, DeployApply, FinalizeDeploy,
  DeployTail), with verify_commit, the two-phase meta deploy, rollback
  refs, the PR-failure comment and forge/pr_merge.rs
- `fetched_sha`, `sha_short`/`pr_number` on approval events, and
  `sha`/`tag` on HelperEvent::ApprovalResolved: only the merge path set
  them

`config_repo`, `merged_pr_for_commit` and `post_pr_comment` move to
forge/pr_comment.rs for the merged-rev deploy's refusal comment.
Approvals v5 drops stored `merge_config_pr` rows; a test reopens a v4
database holding them.

Closes #4850

hive-sh4re/src/approvals.rs

@@ -14,17 +14,10 @@ use serde::{Deserialize, Serialize};
 pub struct Approval {
     pub id: i64,
     pub agent: Ident,
-    #[serde(default)]
     pub kind: ApprovalKind,
     /// Kind-specific payload (git sha / inputs array / schedule
     /// payload / empty). See the Approval struct doc.
     pub commit_ref: String,
-    /// The canonical hive-c0re-vouched sha. For `MergeConfigPr`: the
-    /// reviewed PR head pinned at submit; if the PR head drifts off it
-    /// before merge, hive-c0re cancels the stale approval and re-queues a
-    /// fresh one for re-review.
-    #[serde(default, skip_serializing_if = "Option::is_none")]
-    pub fetched_sha: Option<String>,
     pub requested_at: DateTime<Utc>,
     pub status: ApprovalStatus,
     #[serde(default, skip_serializing_if = "Option::is_none")]
@@ -40,9 +33,7 @@ pub struct Approval {
 /// What action the approval, when granted, will trigger.
 /// Variant-specific payload encoding +  flow lives in
 /// `docs/agent-lifecycle/approvals.md::Approval kinds (wire shapes)`.
-#[derive(
-    Debug, Clone, Copy, Default, Serialize, Deserialize, PartialEq, Eq, strum::IntoStaticStr,
-)]
+#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq, strum::IntoStaticStr)]
 #[serde(rename_all = "snake_case")]
 #[strum(serialize_all = "snake_case")]
 pub enum ApprovalKind {
@@ -51,15 +42,6 @@ pub enum ApprovalKind {
     UpdateMetaInputs,
     /// Add a scheduled prompt to the broker queue.
     SchedulePrompt,
-    /// Merge an operator-reviewed config PR: hive-c0re verifies the
-    /// reviewed PR head, fast-forwards the forge config repo's `main`
-    /// to it, marks the PR merged, then runs the deploy tail. This is the
-    /// sole config-change flow — a manager opens a PR on its
-    /// `agent-configs/<agent>` repo and the operator reviews + approves it.
-    /// `commit_ref` = PR number; `fetched_sha` = the reviewed PR head
-    /// pinned at submit. See `docs/agent-lifecycle/approvals.md`.
-    #[default]
-    MergeConfigPr,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]

hive-sh4re/src/manager.rs

@@ -55,10 +55,6 @@ pub enum HelperEvent {
         status: ApprovalStatus,
         #[serde(default, skip_serializing_if = "Option::is_none")]
         note: Option<String>,
-        #[serde(default, skip_serializing_if = "Option::is_none")]
-        sha: Option<String>,
-        #[serde(default, skip_serializing_if = "Option::is_none")]
-        tag: Option<String>,
     },
     /// A sub-agent's recorded flake rev is stale relative to hyperhive.
     NeedsUpdate { agent: String },