fix(clippy): fix all clippy warnings in hive-ag3nt, hive-forge, hive-matrix-mcp, hive-sh4re

Fixes all clippy -D warnings errors in the crates iris owns:

hive-sh4re:
- doc_lazy_continuation: add blank /// separator in priv_proto.rs
- doc_markdown: backtick PRIVATE_NETWORK=0 / PRIVATE_NETWORK=1

hive-matrix-mcp:
- map_unwrap_or: map().unwrap_or_else() -> map_or_else() in paths.rs
- collapsible_if: if-let chains in wake.rs
- doc_markdown: backtick M_UNKNOWN_TOKEN in main.rs
- cast_possible_truncation: usize/u64 -> u32::try_from in handlers.rs
- map_unwrap_or: map_or_else() in handlers.rs
- manual_let_else: match Ok(r) => r, Err => return -> let Ok in handlers.rs
- unused_async: remove async from list_invites; update socket.rs call site

hive-forge:
- doc_markdown: backtick REQUEST_CHANGES / APPROVED / COMMENT in pr_reviews.rs
- unnecessary_wraps: list_reviews_text returns () not Result<()>
- doc_markdown: backtick start_page / last_page in comments.rs
- cast_possible_truncation: PAGE_SIZE u64 -> usize; remove as usize casts

hive-ag3nt:
- collapsible_if: if-let chains in events.rs and mcp.rs
- single_match_else: match -> if let in events.rs and mcp.rs
- items_after_statements: hoist STATUS_MAX_CHARS const in mcp.rs
- map_unwrap_or: map_or_else() in mcp.rs and mcp_loose_ends.rs
- cast_possible_truncation: usize -> u32::try_from in mcp.rs
- doc_markdown: backtick snake_case in mcp.rs, needs_update/deployed_sha
  in web_ui.rs, HISTORY_CAPACITY in web_ui.rs
- identical_match_arms: combine manage_root_agent | query_agent_state
- redundant_closure: |s| s.to_string() -> ToString::to_string in web_ui.rs
- duration_suboptimal_units: from_secs(3600) -> from_hours(1) in turn.rs

Remaining failures in hive-c0re (39), hive-priv (8), hive-bash-mcp (11)
are owned by damocles.

hive-forge/src/verbs/comments.rs

@@ -26,7 +26,7 @@ use crate::verbs::print_json;
 /// Forgejo's per-page comment cap. The API caps `limit` at 50 even
 /// if a higher value is requested; pin it explicitly so the math
 /// downstream doesn't depend on a hidden default.
-const PAGE_SIZE: u64 = 50;
+const PAGE_SIZE: usize = 50;
 
 #[derive(ClapArgs)]
 pub struct Args {
@@ -112,7 +112,7 @@ fn fetch_tail(client: &Client, repo: &str, number: u64, n: usize) -> Result<Vec<
     // Cap `n` at the actual total so the math below stays in range
     // when the caller asks for more comments than exist.
     let n = n.min(total);
-    let page_size = PAGE_SIZE as usize;
+    let page_size = PAGE_SIZE;
     // 0-based index of the first comment we want; integer-divide to
     // get the 1-based page that contains it.
     let start_idx = total - n;
@@ -145,12 +145,12 @@ mod tests {
 
     /// Pure helper mirroring the page-arithmetic in `fetch_tail`:
     /// given a total comment count + requested tail size, return
-    /// the (start_page, last_page) pair the network loop would
+    /// the (`start_page`, `last_page`) pair the network loop would
     /// walk. Lets us pin the pagination plan — the part that's
     /// easy to off-by-one — without touching the network.
     fn tail_plan(total: usize, n: usize) -> (usize, usize) {
         let n = n.min(total);
-        let page_size = PAGE_SIZE as usize;
+        let page_size = PAGE_SIZE;
         let start_idx = total - n;
         let start_page = (start_idx / page_size) + 1;
         let last_page = (total - 1) / page_size + 1;