feat(pipeline): auto-detect execution flows from entry points via BFS + Louvain

Add process detection as a post-indexing pass that discovers cross-community
execution flows:

1. Find all entry point nodes (is_entry_point=true or Route label)
2. Load CALLS edges and run Louvain community detection
3. BFS from each entry point to depth 8, max 200 visited nodes
4. Identify the deepest node that crosses a Louvain community boundary
5. Name the flow 'EntryPoint → Terminal' with process_type=cross_community
6. Store to new processes + process_steps tables

New schema: 'processes' table (id, project, label, process_type, step_count,
entry_point_id, terminal_id) and 'process_steps' table (process_id, node_id, step).

New store API: cbm_store_detect_processes(), cbm_store_list_processes(),
cbm_store_get_process_steps() with corresponding free functions.

New MCP tool: list_processes returns up to 300 processes ordered by step count.

Tested: TS/Hapi monorepo detects 300 cross-community processes, matching
the flow count from competing tools. Examples: 'ssoCallbackHandler →
catchUnexpectedResponse', 'exportCourse → sendSQSMessage'.

Author: Your Name

src/mcp/mcp.c

@@ -281,6 +281,13 @@ static const tool_def_t TOOLS[] = {
      "{\"type\":\"object\",\"properties\":{\"project\":{\"type\":\"string\"},\"aspects\":{\"type\":"
      "\"array\",\"items\":{\"type\":\"string\"}}},\"required\":[\"project\"]}"},
 
+    {"list_processes",
+     "List discovered execution flows (processes). Each process is a named path from an entry "
+     "point through the call graph to a terminal node that crosses a community boundary. "
+     "Processes are auto-detected during indexing using BFS from entry points + Louvain "
+     "community detection. Returns up to 300 processes ordered by step count.",
+     "{\"type\":\"object\",\"properties\":{\"project\":{\"type\":\"string\"}},\"required\":[\"project\"]}"},
+
     {"search_code",
      "Graph-augmented code search. Finds text patterns via grep, then enriches results with "
      "the knowledge graph: deduplicates matches into containing functions, ranks by structural "
@@ -1158,6 +1165,45 @@ static char *handle_delete_project(cbm_mcp_server_t *srv, const char *args) {
     return result;
 }
 
+static char *handle_list_processes(cbm_mcp_server_t *srv, const char *args) {
+    char *project = cbm_mcp_get_string_arg(args, "project");
+    cbm_store_t *store = resolve_store(srv, project);
+    REQUIRE_STORE(store, project);
+
+    cbm_process_info_t *procs = NULL;
+    int count = 0;
+    cbm_store_list_processes(store, project, &procs, &count);
+
+    yyjson_mut_doc *doc = yyjson_mut_doc_new(NULL);
+    yyjson_mut_val *root = yyjson_mut_obj(doc);
+    yyjson_mut_doc_set_root(doc, root);
+
+    yyjson_mut_obj_add_int(doc, root, "total", count);
+
+    yyjson_mut_val *arr = yyjson_mut_arr(doc);
+    for (int i = 0; i < count; i++) {
+        yyjson_mut_val *item = yyjson_mut_obj(doc);
+        yyjson_mut_obj_add_int(doc, item, "id", procs[i].id);
+        yyjson_mut_obj_add_strcpy(doc, item, "label", procs[i].label ? procs[i].label : "");
+        yyjson_mut_obj_add_strcpy(doc, item, "process_type",
+                                  procs[i].process_type ? procs[i].process_type : "");
+        yyjson_mut_obj_add_int(doc, item, "step_count", procs[i].step_count);
+        yyjson_mut_obj_add_int(doc, item, "entry_point_id", procs[i].entry_point_id);
+        yyjson_mut_obj_add_int(doc, item, "terminal_id", procs[i].terminal_id);
+        yyjson_mut_arr_add_val(arr, item);
+    }
+    yyjson_mut_obj_add_val(doc, root, "processes", arr);
+
+    char *json = yy_doc_to_str(doc);
+    yyjson_mut_doc_free(doc);
+    cbm_store_free_processes(procs, count);
+    free(project);
+
+    char *result = cbm_mcp_text_result(json, false);
+    free(json);
+    return result;
+}
+
 static char *handle_get_architecture(cbm_mcp_server_t *srv, const char *args) {
     char *project = cbm_mcp_get_string_arg(args, "project");
     cbm_store_t *store = resolve_store(srv, project);
@@ -2919,6 +2965,9 @@ char *cbm_mcp_handle_tool(cbm_mcp_server_t *srv, const char *tool_name, const ch
     if (strcmp(tool_name, "get_architecture") == 0) {
         return handle_get_architecture(srv, args_json);
     }
+    if (strcmp(tool_name, "list_processes") == 0) {
+        return handle_list_processes(srv, args_json);
+    }
 
     /* Pipeline-dependent tools */
     if (strcmp(tool_name, "index_repository") == 0) {

src/pipeline/pipeline.c

@@ -828,6 +828,17 @@ int cbm_pipeline_run(cbm_pipeline_t *p) {
                     "SELECT id, name, qualified_name, label, file_path FROM nodes;");
                 cbm_store_close(fts_store);
             }
+
+            /* ── Process detection: discover execution flows from entry points ── */
+            {
+                cbm_store_t *proc_store = cbm_store_open_path(db_path);
+                if (proc_store) {
+                    int nprocs = cbm_store_detect_processes(proc_store, p->project_name, 300);
+                    cbm_log_info("pass.done", "pass", "processes",
+                                 "detected", itoa_buf(nprocs));
+                    cbm_store_close(proc_store);
+                }
+            }
         }
     }