mise: drop global python, add venv auto-activation + idiomatic version files

dot_config/fish/conf.d/zz_03_interactive.fish

@@ -36,4 +36,11 @@ if status is-interactive
             printf '\e[6 q'
         end
     end
+
+    # Auto-activate Python virtualenvs on `cd` (any repo with a .venv). Required
+    # because we use mise --shims, which don't run the cd hook that mise's
+    # python.uv_venv_auto relies on. The function autoloads from
+    # ~/.config/fish/functions/__auto_venv.fish; calling it here loads the file
+    # (registering its --on-variable PWD handler) and activates the start dir.
+    __auto_venv
 end

dot_config/fish/functions/__auto_venv.fish

@@ -0,0 +1,33 @@
+function __auto_venv --on-variable PWD --description 'Auto-activate the nearest Python .venv on cd'
+    # Auto-activate Python virtualenvs on `cd` for any repo that has a .venv —
+    # including uv projects: mise's python.uv_venv_auto only fires through the
+    # `mise activate` HOOK, which we don't run (we use --shims), so this function
+    # owns ALL interactive venv activation. Activates the nearest ancestor .venv,
+    # deactivates on leaving its tree, and never touches a venv we didn't activate
+    # (manual / mise) — we only ever deactivate the one we started (__auto_venv_dir).
+    #
+    # Autoloaded: zz_03_interactive.fish calls __auto_venv once, which loads this
+    # file (registering the --on-variable PWD handler) and activates the start dir.
+    set -l found
+    set -l dir $PWD
+    while true
+        if test -e "$dir/.venv/bin/activate.fish"
+            set found "$dir/.venv"
+            break
+        end
+        test "$dir" = / ; and break
+        set dir (path dirname $dir)
+    end
+
+    if test -n "$found"
+        test "$VIRTUAL_ENV" = "$found"; and return # already active
+        if test -z "$VIRTUAL_ENV"; or set -q __auto_venv_dir
+            functions -q deactivate; and deactivate # swap out our previous one
+            source "$found/bin/activate.fish"
+            set -g __auto_venv_dir "$found"
+        end
+    else if set -q __auto_venv_dir
+        functions -q deactivate; and deactivate
+        set -e __auto_venv_dir
+    end
+end

dot_config/mise/config.toml.tmpl

@@ -1,9 +1,17 @@
 {{ if contains "dev" .tags -}}
+# NOTE: python intentionally NOT a global tool. mise shims fall through to the
+# next binary on PATH when a tool isn't configured, so leaving python out here
+# makes `python3`/`pip` resolve to /usr/bin/python3 everywhere by default —
+# which is what pacman/paru packages (#!/usr/bin/env python3, e.g. virt-manager,
+# needs system gi/PyGObject) expect. Opt into mise python per-project via a
+# .mise.toml (`mise use python@<ver>`), or ad-hoc with `mise shell python@latest`.
 [tools]
 bun = "latest"
 node = "latest"
 rust = "latest"
 go = "latest"
 java = "latest"
-python = "latest"
+
+[settings]
+idiomatic_version_file_enable_tools = ["node", "python", "go", "ruby", "java", "rust"]
 {{ end -}}