deps: global gitlibs-style clone cache + :tasks runner

Git clones now default to a shared, sha-immutable cache —
$JOLT_GITLIBS, else <config-dir>/gitlibs — instead of a per-project
./jpm_tree, the tools.gitlibs ~/.gitlibs model. Passing tree
explicitly still works (tests do). The resolved-roots cache moves
out of the clone tree to the project-local .cpcache/jolt-deps.jdn,
since roots depend on the project while clones don't.

deps.edn grows :tasks, the honest subset of babashka's: a string
task is a shell command, a map task is {:main-opts [...] :doc}.
jolt-deps tasks lists them (merged user+project), jolt-deps task
NAME runs one. Bare-expression tasks are out of scope: the reader
hands back parsed data and round-tripping to source is fragile.

Also fixes load-config skipping the symbol-key normalization when
only one config file existed — :tasks/:deps keys stayed raw reader
symbols (which embed positions and never compare equal), so lookups
missed. Regression rows in deps-tasks-test; docs updated for the
whole tools.deps surface (aliases, -A/-M, user config, conflicts,
gitlibs cache, tasks).

docs/building-and-deps.md

@@ -63,6 +63,10 @@ jolt-deps path             # print the resolved roots (':'-joined)
 jolt-deps run FILE [args]  # resolve, then run `jolt FILE …`
 jolt-deps repl             # resolve, then start a REPL
 jolt-deps -e EXPR [args]   # resolve, then evaluate EXPR
+jolt-deps -A:dev path      # include the :dev alias's extra paths/deps
+jolt-deps -M:test [args]   # run the :test alias's :main-opts through jolt
+jolt-deps tasks            # list :tasks from deps.edn
+jolt-deps task NAME [args] # run a task
 ```
 
 `jolt-deps` launches the `jolt` binary it finds on `PATH` (override with
@@ -88,10 +92,27 @@ jolt-deps run -m myapp.main
   dependency's own `deps.edn` are resolved too.
 - **local deps** — `{:local/root "../path"}`.
 - The project's own `:paths` (default `["src"]`) are included.
+- **aliases** — `:aliases {:dev {:extra-paths ["dev"] :extra-deps {…}
+  :main-opts ["-e" "…"]}}`, selected with `-A:dev` (or several: `-A:dev:test`).
+  `:extra-paths`/`:extra-deps` accumulate across selected aliases;
+  `:main-opts` is last-wins and runs via `-M:alias`.
+- **user config** — a `deps.edn` under `$JOLT_CONFIG` (else
+  `$XDG_CONFIG_HOME/jolt`, else `~/.jolt`) merges beneath the project's, the
+  way `~/.clojure/deps.edn` does: `:deps`/`:aliases`/`:tasks` merge per key
+  with the project winning.
+- **tasks** — `:tasks {clean "rm -rf target" test {:doc "run the suite"
+  :main-opts ["-e" "(run-tests)"]}}`. A string task is a shell command; a map
+  task runs jolt with its `:main-opts`. `jolt-deps tasks` lists, `jolt-deps
+  task NAME` runs.
 
-Resolution reuses jpm's git fetch and cache (a dependency is cloned once into
-`jpm_tree/.cache` and reused). Resolved roots are cached on a hash of `deps.edn`,
-so an unchanged `deps.edn` doesn't re-fetch.
+Conflicts resolve the tools.deps way: resolution is breadth-first, so a
+top-level coordinate always beats a transitive one for the same lib, and
+conflicting coordinates print a warning naming both.
+
+Git clones land in a global, sha-immutable cache shared across projects —
+`$JOLT_GITLIBS`, else `<config-dir>/gitlibs` (the `~/.gitlibs` model). The
+resolved roots are cached per project in `.cpcache/jolt-deps.jdn`, keyed on a
+hash of the project `deps.edn` + the user `deps.edn` + the selected aliases.
 
 ### What's not
 

docs/tools-deps.md

@@ -42,11 +42,29 @@ syntax overlap for the `:deps`/`:paths` subset), then walks `:deps`:
 - `:mvn/*` and anything else → ignored.
 
 Each resolved dependency contributes its own `:paths` (default `["src"]`) as
-source roots, and we recurse into its `deps.edn` for transitive deps. The result
+source roots; the walk is **breadth-first** so every top-level coordinate
+registers before any transitive one — a top-level pin always wins, matching
+tools.deps, and a coordinate conflict warns on stderr naming both. The result
 is a de-duplicated, ordered list of directories. `resolve-deps-cached` memoizes
-that list in the tree keyed on a hash of `deps.edn`, so an unchanged file doesn't
-re-fetch. jpm is loaded lazily (`require`, not `import`) so it's pulled in only
-when resolving — never embedded in a built binary.
+that list in the project-local `.cpcache/jolt-deps.jdn`, keyed on a hash of the
+project `deps.edn` + the user-level `deps.edn` + the selected aliases. jpm is
+loaded lazily (`require`, not `import`) so it's pulled in only when resolving —
+never embedded in a built binary.
+
+Three tools.deps features are mirrored in reduced form. **Aliases**: `:aliases`
+entries supply `:extra-paths`/`:extra-deps` (accumulate across the aliases
+selected with `-A:a:b`) and `:main-opts` (last-wins, run with `-M:alias`).
+**User config**: a `deps.edn` under `$JOLT_CONFIG` (else
+`$XDG_CONFIG_HOME/jolt`, else `~/.jolt`) merges beneath the project file,
+per key, project wins. **Tasks**: the honest subset of babashka's — a string
+task is a shell command, a map task is `{:main-opts […] :doc "…"}`; bare
+Clojure expressions aren't supported because the reader hands back parsed
+data, and round-tripping it to source isn't worth the fragility.
+
+Clones default to a global sha-immutable cache (`$JOLT_GITLIBS`, else
+`<config-dir>/gitlibs`) shared across projects, the `tools.gitlibs`
+`~/.gitlibs` model; per-project trees remain available by passing `tree`
+explicitly.
 
 The loader (`evaluator.janet/find-ns-file`) resolves a namespace by searching the
 context's `:source-paths` in order (the stdlib `src/jolt` first), trying `<ns>.clj`