feat(coderd): add consolidated /debug/profile endpoint for pprof collection (#22892)

## Summary

Adds a new `GET /api/v2/debug/profile` endpoint that collects multiple
pprof profiles in a single request and returns them as a tar.gz archive.
This allows collecting profiles (including block and mutex) without
requiring `CODER_PPROF_ENABLE` to be set, and without restarting
`coderd`.

Closes #21679

## What it does

The endpoint:
- Temporarily enables block and mutex profiling (normally disabled at
runtime)
- Runs CPU profile and/or trace for a configurable duration (default
10s, max 60s)
- Collects snapshot profiles (heap, allocs, block, mutex, goroutine,
threadcreate)
- Returns a tar.gz archive containing all requested `.prof` files
- Uses an atomic bool to prevent concurrent collections (returns 409
Conflict)
- Is protected by the existing debug endpoint RBAC (owner-only)

**Supported profile types:** cpu, heap, allocs, block, mutex, goroutine,
threadcreate, trace

**Query parameters:**
- `duration`: How long to run timed profiles (default: `10s`, max:
`60s`)
- `profiles`: Comma-separated list of profile types (default:
`cpu,heap,allocs,block,mutex,goroutine`)

## Additional changes

- **SDK client method** (`codersdk.Client.DebugCollectProfile`) for easy
programmatic access
- **`coder support bundle --pprof` integration**: tries the consolidated
endpoint first, falls back to individual `/debug/pprof/*` endpoints for
older servers
- **8 new tests** covering defaults, custom profiles, trace+CPU,
validation errors, authorization, and conflict detection

coderd/apidoc/docs.go

@@ -869,6 +869,28 @@ const docTemplate = `{
                 }
             }
         },
+        "/debug/profile": {
+            "post": {
+                "security": [
+                    {
+                        "CoderSessionToken": []
+                    }
+                ],
+                "tags": [
+                    "Debug"
+                ],
+                "summary": "Collect debug profiles",
+                "operationId": "collect-debug-profiles",
+                "responses": {
+                    "200": {
+                        "description": "OK"
+                    }
+                },
+                "x-apidocgen": {
+                    "skip": true
+                }
+            }
+        },
         "/debug/tailnet": {
             "get": {
                 "security": [

coderd/apidoc/swagger.json

@@ -752,6 +752,26 @@
 				}
 			}
 		},
+		"/debug/profile": {
+			"post": {
+				"security": [
+					{
+						"CoderSessionToken": []
+					}
+				],
+				"tags": ["Debug"],
+				"summary": "Collect debug profiles",
+				"operationId": "collect-debug-profiles",
+				"responses": {
+					"200": {
+						"description": "OK"
+					}
+				},
+				"x-apidocgen": {
+					"skip": true
+				}
+			}
+		},
 		"/debug/tailnet": {
 			"get": {
 				"security": [