fix: initialize installer manifest helper before codex install

[Orinks]

Summary

• fix the installer bug where install.sh --global --codex could fail with add_manifest_entry: command not found
• initialize the manifest helper before any installer path can call it
• ensure fresh global installs create the target directory before touching the manifest

Root cause

The Codex install path called add_manifest_entry, but that helper was defined later inside the Claude file-copy branch. On global/plugin installs, that branch was skipped, so the function never existed when Codex tried to use it.

Moving the helper earlier exposed a second issue on fresh global installs: the target directory needed to be created before the manifest file could be touched.

Verification

I verified the relevant installer paths against this branch non-interactively:

• bash install.sh --global
• bash install.sh --project
• bash install.sh --global --codex
• bash install.sh --project --codex
• bash install.sh --global --gemini
• bash install.sh --project --gemini
• bash install.sh --global --cli
• bash install.sh --project --cli

All eight completed with exit status 0.

For the Codex paths, I also verified that the install produced:

• .codex/AGENTS.md
• .codex/config.toml
• .codex/roles/ with all role files
• correct manifest entries for Codex config, roles, install scope, and AGENTS path

Scope

Tight fix to installer execution order and target-dir initialization only. No unrelated cleanup.

[Copilot]

Pull request overview

Fixes an installer execution-order bug where the --codex path could call add_manifest_entry before it was defined, particularly in global/plugin installs, and ensures the target directory exists before manifest operations.

Changes:

• Initialize the installer manifest (and add_manifest_entry helper) immediately after TARGET_DIR is determined.
• Ensure fresh installs create $TARGET_DIR before touching the manifest.
• Remove the now-redundant manifest/helper definition from the later file-copy branch.

[Copilot]

Creating/touching the manifest unconditionally here changes later control flow: cleanup_old_install() (used during global plugin installs) currently runs whenever ~/.claude/.a11y-agent-manifest exists, so this new touch makes it run (and delete the manifest) even on fresh plugin installs, showing a misleading cleanup message. Consider making cleanup_old_install require a non-empty/valid manifest (e.g., -s or pattern check) or making add_manifest_entry create/touch the manifest lazily so the presence check still reflects a previous non-plugin install.

Suggested change

touch "$MANIFEST_FILE"

[Copilot]

Now that add_manifest_entry is defined globally, any later checks that use “function exists” as a proxy for “file-copy install happened” will always pass. In particular, the install-scope recording near the end of the script will now always write to the manifest (including plugin-only installs), which seems to contradict its comment and prior behavior. Suggest switching that guard to an explicit state flag (e.g., PLUGIN_INSTALL / FILE_COPY_INSTALL) or checking for expected manifest entries instead of testing for the function.