feat(nvim): add tmux provider support for OpenCode plugin

[pablon]

Summary

• Add automatic provider detection based on TMUX environment variable
  • Add tmux provider support for OpenCode plugin.
  • Use tmux provider inside tmux, otherwise fallback to snacks.

Provider Selection (Line 106)

local provider = vim.env.TMUX and "tmux" or "snacks"

• Conditional logic: Checks if running inside tmux
• If TMUX env var exists → use "tmux" provider
• Otherwise → use "snacks" provider (snacks.nvim)

Provider Configuration (Lines 107-129)

TMUX Provider (Lines 110-116)

tmux = {
  win = {
    enter = true,             -- Enter the window
    position = "left",        -- Split on left side
  },
  focus = true,               -- Focus the pane when opening
  allow_passthrough = false,  -- Disable tmux passthrough mode
}

Snacks Provider (Lines 117-127)

snacks = {
  auto_close = true,          -- Close when done
  focus = true,               -- Focus the window
  win = {
    enter = true,             -- Enter the window
    position = "left",        -- Split on left side
    bo = {
      filetype = "opencode_terminal",  -- Custom filetype for syntax/behavior
    },
  },
}

---

Key Design Patterns

1. Mode Consistency: All commands work in normal + visual modes except toggle (normal only)
2. Auto-submit Pattern: Every command uses { submit = true } to skip confirmation
3. Context Prefixes: Uses @this, @file to specify scope
4. Environment Adaptation: Automatically chooses UI provider based on tmux presence
5. Hierarchical Keybindings: <leader>a -> <leader>ap -> <leader>ap[e/f/d/r/t/o]

---

Workflow Example

1. User presses <leader>ape on selected code
2. OpenCode calls prompt("explain", { submit = true })
3. Plugin opens in left split (snacks) or tmux pane
4. AI explains the selected code
5. Window auto-closes when done (auto_close = true)

PS: Aguante bigote!!! 👨🏻