feat: add plugin v1 system

Add manifest-driven plugin actions, event hooks, pane entrypoints, link handlers, and host APIs.

Support plugin link, GitHub install, build commands, installed plugin registry, pane movement, runtime context, and plugin docs.

1 files changed, 22 insertions, 3 deletions

diff --git a/src/cli/agent.rs b/src/cli/agent.rs
index 8c3c907b..80148046 100644
--- a/src/cli/agent.rs
+++ b/src/cli/agent.rs
@@ -1,3 +1,5 @@
+use std::collections::HashMap;
+
 use crate::api::schema::{
     AgentReadParams, AgentRenameParams, AgentSendParams, AgentStartParams, AgentStatus,
     AgentTarget, EmptyParams, Method, ReadFormat, ReadSource, Request, Subscription,
@@ -267,12 +269,12 @@ fn matched_rule_region_preview<'a>(
 
 fn agent_start(args: &[String]) -> std::io::Result<i32> {
     let Some(name) = args.first() else {
-        eprintln!("usage: herdr agent start <name> [--cwd PATH] [--workspace ID] [--tab ID] [--split right|down] [--focus|--no-focus] -- <argv...>");
+        eprintln!("usage: herdr agent start <name> [--cwd PATH] [--workspace ID] [--tab ID] [--split right|down] [--env KEY=VALUE] [--focus|--no-focus] -- <argv...>");
         return Ok(2);
     };
 
     let Some(separator) = args.iter().position(|arg| arg == "--") else {
-        eprintln!("usage: herdr agent start <name> [--cwd PATH] [--workspace ID] [--tab ID] [--split right|down] [--focus|--no-focus] -- <argv...>");
+        eprintln!("usage: herdr agent start <name> [--cwd PATH] [--workspace ID] [--tab ID] [--split right|down] [--env KEY=VALUE] [--focus|--no-focus] -- <argv...>");
         return Ok(2);
     };
     if separator == args.len() - 1 {
@@ -285,6 +287,7 @@ fn agent_start(args: &[String]) -> std::io::Result<i32> {
     let mut tab_id = None;
     let mut split = None;
     let mut focus = false;
+    let mut env = HashMap::new();
 
     let mut index = 1;
     while index < separator {
@@ -329,6 +332,21 @@ fn agent_start(args: &[String]) -> std::io::Result<i32> {
                 focus = false;
                 index += 1;
             }
+            "--env" => {
+                let Some(value) = args.get(index + 1).filter(|_| index + 1 < separator) else {
+                    eprintln!("missing value for --env");
+                    return Ok(2);
+                };
+                let (key, value) = match super::parse_env_assignment(value) {
+                    Ok(pair) => pair,
+                    Err(err) => {
+                        eprintln!("{err}");
+                        return Ok(2);
+                    }
+                };
+                env.insert(key, value);
+                index += 2;
+            }
             other => {
                 eprintln!("unknown option: {other}");
                 return Ok(2);
@@ -346,6 +364,7 @@ fn agent_start(args: &[String]) -> std::io::Result<i32> {
             split,
             focus,
             argv: args[separator + 1..].to_vec(),
+            env,
         }),
     })?)
 }
@@ -656,7 +675,7 @@ fn print_agent_help() {
     eprintln!("  herdr agent focus <target>");
     eprintln!("  herdr agent wait <target> --status <idle|working|blocked|unknown> [--timeout MS]");
     eprintln!("  herdr agent attach <target> [--takeover]");
-    eprintln!("  herdr agent start <name> [--cwd PATH] [--workspace ID] [--tab ID] [--split right|down] [--focus|--no-focus] -- <argv...>");
+    eprintln!("  herdr agent start <name> [--cwd PATH] [--workspace ID] [--tab ID] [--split right|down] [--env KEY=VALUE] [--focus|--no-focus] -- <argv...>");
     eprintln!("  herdr agent explain <target> [--json]");
     eprintln!("  herdr agent explain --file PATH --agent LABEL [--json]");
     eprintln!("  targets accept terminal ids, unique agent names, detected/reported agent labels, and legacy pane ids");