feat(#1877): restructure hive-forge into pr/issue sub-verbs

Group issue/PR operations under `pr` and `issue` parent commands
(`hive-forge pr close 42`, `issue create …`, `pr status --pr 42`) per the
operator decision — kind-namespaced verbs replace the flat surface.

- new `verbs::pr_cmd` / `verbs::issue_cmd` parent commands wrap the existing
  per-verb modules (reuse their Args + run fns) under `#[command(subcommand)]`.
- kind-validation (the win over the old generic verbs): the generics that work
  on both (view/comment/comments/close/labels/assign/timeline) call
  `assert_kind` first, so `pr close <issue>` / `issue close <pr>` are rejected
  with a 'use the other command' message. PR-only / issue-only verbs are
  kind-correct by construction. `number` exposed `pub(crate)` on the shared
  verbs so the wrappers can probe it.
- every flat kind verb (`close`, `pr-create`, `pr-status`, `issue-edit`, …)
  kept as a `#[command(hide = true)]` back-compat alias — still parses, dropped
  from --help; removed in a later sweep once usage migrates. (`pr`/`issue`
  bare-show become `pr show` / `issue show` — the names are now parents.)
- docs/tools/forge.md documents the new surface + the deprecated aliases.

cargo build/clippy/fmt clean, 54 tests pass; --help surface + alias parsing
smoke-tested.

hive-forge/src/verbs/mod.rs

@@ -17,6 +17,7 @@ pub mod comment_show;
 pub mod comments;
 pub mod diff;
 pub mod issue;
+pub mod issue_cmd;
 pub mod issue_create;
 pub mod issue_edit;
 pub mod labels;
@@ -24,6 +25,7 @@ pub mod lint;
 pub mod list;
 pub mod milestone;
 pub mod pr;
+pub mod pr_cmd;
 pub mod pr_commits;
 pub mod pr_create;
 pub mod pr_merge;
@@ -52,6 +54,37 @@ pub(crate) fn print_json(v: &Value) -> Result<()> {
     Ok(())
 }
 
+/// Issue-vs-PR kind, for the `pr <verb>` / `issue <verb>` sub-command
+/// validation.
+#[derive(Clone, Copy)]
+pub(crate) enum Kind {
+    Pr,
+    Issue,
+}
+
+/// Verify `number` is the expected kind before a kind-namespaced verb (one
+/// of the generics that work on both — close/comment/labels/…) acts on it —
+/// the validation win the `pr <verb>` / `issue <verb>` split buys over the
+/// old generic verbs. Forgejo's `/issues/{n}` endpoint serves both issues and
+/// PRs and marks PRs with a non-null `pull_request` field, so one GET
+/// classifies it. Errors with a "use the other command" message on mismatch.
+pub(crate) fn assert_kind(client: &Client, number: u64, expected: Kind) -> Result<()> {
+    let repo = client.repo();
+    let v = client.get_json(&format!("/repos/{repo}/issues/{number}"))?;
+    let is_pr = v.get("pull_request").is_some_and(|p| !p.is_null());
+    match (expected, is_pr) {
+        (Kind::Pr, false) => {
+            anyhow::bail!(
+                "#{number} is an issue, not a PR — use `hive-forge issue <verb> {number}`"
+            )
+        }
+        (Kind::Issue, true) => {
+            anyhow::bail!("#{number} is a PR, not an issue — use `hive-forge pr <verb> {number}`")
+        }
+        _ => Ok(()),
+    }
+}
+
 /// Minimal RFC 3986 unreserved-set percent encoder. Covers the subset of
 /// characters that show up in the values we splice into request paths —
 /// usernames, label names, artifact names — without pulling in a fresh