refactor(env): rename env_resolve.py -> env.py; env_resolve() -> resolve_env_into()

Module name aligns with the others (manifest, pipelock, network,
log) — nouns/noun-y, not verb phrases. The function name now reads
naturally at the call site: resolve_env_into(manifest, agent,
env_file, args_file).

claude_bottle/env.py

@@ -0,0 +1,140 @@
+"""Env resolver. Walks the env entries for one agent and produces:
+
+  1. The list of `docker run` arg fragments needed to forward each var.
+     Both `secret` and `interpolated` entries become `-e NAME` (no
+     `=value`) so Docker inherits the value from this process env
+     without rendering it on argv or persisting it to disk.
+     Only `literal` entries are written to a host-disk env-file.
+  2. The export side-effect of populating this process's env with
+     secret values prompted from the user, and with interpolated
+     values copied from the matching host var, so `-e NAME` actually
+     has something to inherit.
+
+Each env entry is a string. Mode is selected by sentinel prefix:
+  "?"           → secret (prompt at runtime). Bare "?" uses default prompt;
+                  "?<message>" uses <message> as the prompt body.
+  "${HOST_VAR}" → interpolated from $HOST_VAR in the host process env
+  any other str → literal (the string is the value verbatim)
+
+Critical rules:
+  - NEVER echo, log, or interpolate the value of a secret or
+    interpolated env var. Both are treated as potentially sensitive:
+    nothing about their value (other than presence) ever lands on
+    disk, in a log line, or on argv.
+  - The env-file written for literals lives under mktemp -d with mode
+    600, removed by the caller's cleanup.
+  - Errors mention only the variable NAME, never any portion of the value.
+"""
+
+from __future__ import annotations
+
+import getpass
+import os
+import re
+import sys
+from pathlib import Path
+
+from .log import die
+from .manifest import Manifest
+
+_INTERPOLATED_RE = re.compile(r"^\$\{([A-Za-z_][A-Za-z0-9_]*)\}$")
+
+
+def env_entry_kind(raw: str) -> str:
+    """Returns 'secret', 'interpolated', or 'literal'."""
+    if raw.startswith("?"):
+        return "secret"
+    if _INTERPOLATED_RE.match(raw):
+        return "interpolated"
+    return "literal"
+
+
+def env_entry_secret_prompt(raw: str) -> str:
+    """For a secret entry, the prompt body (after the leading '?').
+    Empty for bare '?', meaning use default."""
+    if raw.startswith("?"):
+        return raw[1:]
+    return ""
+
+
+def env_entry_interpolated_from(raw: str) -> str:
+    """For an interpolated entry, the host var name between '${' and '}'."""
+    m = _INTERPOLATED_RE.match(raw)
+    if not m:
+        return ""
+    return m.group(1)
+
+
+def _read_secret_silent(name: str, prompt_body: str) -> str:
+    """Read a secret value from the controlling tty without echoing.
+    The "(input hidden): " tail is always appended; manifest authors
+    write only the message text."""
+    if not (sys.stdin.isatty() or sys.stderr.isatty()):
+        # Fall back to /dev/tty so this still works when stdin is a pipe.
+        try:
+            tty = open("/dev/tty", "r+")
+        except OSError:
+            die(
+                f"cannot prompt for secret '{name}': no tty available. "
+                f"Run from an interactive shell."
+            )
+        prompt = (
+            f"{prompt_body} (input hidden): "
+            if prompt_body
+            else f"claude-bottle: secret value for {name} (input hidden): "
+        )
+        value = getpass.getpass(prompt, stream=tty)
+        tty.close()
+    else:
+        prompt = (
+            f"{prompt_body} (input hidden): "
+            if prompt_body
+            else f"claude-bottle: secret value for {name} (input hidden): "
+        )
+        value = getpass.getpass(prompt)
+    if not value:
+        die(f"empty value provided for secret '{name}'. Re-run and supply a value.")
+    return value
+
+
+def resolve_env_into(
+    manifest: Manifest,
+    agent: str,
+    env_file: Path,
+    out_args: Path,
+) -> None:
+    """Iterate the agent's env entries:
+      - secret:       always prompt; export into this process; append `-e NAME` to out_args
+      - interpolated: copy host value; export under target name; append `-e NAME`
+      - literal:      append `NAME=VALUE` to env_file
+    """
+    bottle = manifest.bottle_for(agent)
+    for name, raw in bottle.env.items():
+        if not name:
+            continue
+        kind = env_entry_kind(raw)
+        if kind == "secret":
+            prompt_body = env_entry_secret_prompt(raw)
+            value = _read_secret_silent(name, prompt_body)
+            os.environ[name] = value
+            with out_args.open("a") as f:
+                f.write(f"-e\n{name}\n")
+        elif kind == "interpolated":
+            host_var = env_entry_interpolated_from(raw)
+            host_value = os.environ.get(host_var, "")
+            if not host_value:
+                die(
+                    f"env entry {name} is interpolated from ${host_var}, "
+                    f"but ${host_var} is unset or empty in the host environment."
+                )
+            os.environ[name] = host_value
+            with out_args.open("a") as f:
+                f.write(f"-e\n{name}\n")
+        else:  # literal
+            if "\n" in raw:
+                die(
+                    f"env entry {name} (literal) contains a newline; "
+                    f"docker --env-file cannot represent multi-line values."
+                )
+            with env_file.open("a") as f:
+                f.write(f"{name}={raw}\n")